The use of retained gate-charge to hold a FET switch in an essentially bistable state is well-known, being the operational basis of ubiquitous DRAM's used in computers. The use of retained gate-charge to hold the state of a power switch is less common, but is known in synchronous rectifier applications. U.S. Pat. Nos. 7,035,120, 6,940,732, 6,839,246, and 6,377,477 exemplify such use, in which gate-charge and the means for removing same are automatically derived from a power transformer being switched. Other switches have stored charge external to the switch device itself as exemplified by U.S. Pat. Nos. 6,686,729 and 6,600,145. The field of power conversion is replete with examples of switches driven without exploiting gate-charge retention. In such cases, switch enhancement voltage must be provided during the entire switch ON time. For well-known “high-side” switches, and for bipolar switches, either a floating enhancement-voltage supply, or an inductor or transformer requiring reset time, become necessary inconveniences. Usually, isolated control-signal drivers must be provided with floating supplies.